Chapter 10 Fault Diagnosis; Events, Malfunctions, And Operating Instructions In General; Error Code Types; Table 12 - Structure Of A Diagnostic Trouble Code (Dtc) - intellic Bosch EFAS-4.10 Workshop Manual

Chapter 10 Fault diagnosis

10.1

Events, malfunctions, and operating instructions in general

The smart tachograph EFAS monitors all relevant system functions of the tachograph system cyclically. This includes the smart
tachograph EFAS itself with individual components such as printer, keyboard, display unit and card slots as well as the motion
sensor connected and the instrument panel connected via the CAN bus.
For smart tachographs, one differentiates between malfunctions and errors whose logging is prescribed as mandatory by the
legislator by means of the Regulation (EC) No. 1360/2002 (so-called EFT) and those, which are used for error analysis and for
diagnosis of the controller (so-called DTC). Furthermore, the smart tachograph EFAS can output additional operating instruc-
tions and specific service messages on the display unit.
During fault diagnosis one can, in general, differentiate between events, malfunctions and operating instructions.
Events
Malfunctions
User warning messages
Please note that events can also be caused by a defect and must then be evaluated as errors. The event, power supply
interruption, for example, occurs when the device has been disconnected from the supply voltage of the vehicle battery.
This event is a normal process when installing the device or replacing the vehicle battery in the workshop. If, however, the event
occurs during normal operation of the vehicle, then there is either a defect in the power supply or in the smart tachograph.
Even operation instructions can be caused by errors. For example, the operator instruction "> Printer < - No paper"
requests that paper be fed into the printer. If the operator instruction continues to be displayed even after feeding the paper,
then, probably, there is a defect in the printer equipment. These messages are output on the display unit of the smart tacho-
graph EFAS only, and they are not stored permanently. In general, these operator instructions are indications of short time
delays of operations in progress (waiting messages).
10.2

Error code types

EFAS differentiates between three different error code types, described in the following.
Type 1, EFT:
Events and malfunctions of type 1, so-called "Events and Fault Types" (EFT) in accordance with the Regulation (EC) No. 2016/799,
are stored permanently in the mass memory of the device conforming to the EU specifications with the starting time point and
the ending time point, as long as the device is activated and is not in the CALIBRATION mode. An EFT is a defined, two-character
hexadecimal code in accordance with the Regulation (EC) No. 2016/799. In printouts, it is given only in decimal format along
with its associated symbol.
Recorded events and malfunctions of this type can be printed out via the printer and read via the download interface of the
device as a data record. The occurrence of such an event or malfunction is indicated by means of a message on the display
unit of the EFAS. In the process, the red warning light blinks and a warning tone is output optionally (depending on the user
setting). The message must be acknowledged by the user with the help of a keystroke. This code is not displayed on printouts
or messages on the display unit if the associated symbol is unequivocal.
Type 2, DTC:
Events and errors of type 2 are specified in the standard ISO 16844-7 for a tachograph system. They are termed as so-called
"Diagnostic Trouble Codes" (DTC). The occurrence of a DTC is saved in a special fault memory. A DTC is a 10-character hexadec-
imal code (five bytes).
Table 12 — Structure of a Diagnostic Trouble Code (DTC)
Severity byte Functional unit
80
(Malfunction in data communication to the motion sensor / speed sensor)
DTCs do not appear on the printout, display, or download data. In general, DTCs are read out with the help of an inspection /
Workshop Manual
Digital Tachograph EFAS-4.10
Processes such as, e.g. infringements, which are recorded by the device, but, however, do not affect
the function of the smart tachographs.
Errors, which basically indicate a defect in the device or that it has been manipulated. On occurrence
of a malfunction, the function of the tachograph system can be impaired or no longer assured.
If a user error or an action by the user required to be issued operating notes.
High byte
00 00
Middle byte Low byte
23
43
Status byte
80 + xx
e.g. 2F